Saturday, December 2, 2023

Monitor Color Calibration... On the Cheap (English)

Datatalk.

You'd expect to find tons of apps that would claim to aid in monitor calibration, but there aren't that many... and the few I tried were not very impressive. So, unless you have an actual colorimeter, you're pretty much on your own.

I tried some things but in the end I had to settle for the cheapest solution: eyeball it. (Which is always wrong, but sometimes all that's left.)


Why calibrate?

  • because you want your videos / graphics on your PC to look the same on other devices
  • because you have more than one monitor and you want the images shown on both to look the same
  • or both 😁


Eyeball it

If you take the eyeball route, then find one device that will be your reference. The better it is, the better your end result. Reviews show that my Samsung Galaxy A54 should be reasonable, though it appears people owning a Huawei P20 or an Apple device may have a better reference.

So, when eyeballing it, you just compare the image / color on your screen with some other device... That's all. It isn't perfect, but it is doable.

On your device, you may have to switch your display mode to fixed brightness, non auto adjusting, non vivid mode, sleep adjust / night time / blue color filter whatever it is called off, and put contrast and brightness options to average.


Grey is the new... grey?

Up front a warning: tweak only what you have to, and as little as possible. A minor difference is better than reducing the color accuracy and color depth of your screens. Without a meter and / or a good eye it's way to easy to make things worse.

Start with brightness / contrast / gamma before adjusting anything else.


Step by step

1.1 Warm up

Make sure your monitors are 'warm' (literally), ie. that the screens have been on for half an hour or so. If necessary, disable any screen savers and power savers, or simply work-work-work until you're ready to calibrate 😏


1.2 Reference device

Don't forget! If you have a reference device (like an iPhone or something else) that you trust, then disable any options such as vivid, warm etc. on the phone


2.1 B&W on monitor 1

Use a color / B&W chart (image) with enough individual blocks ranging from black to white, and tweak brightness and contrast and gamma on the monitor itself (most monitors don't have gamma as an option) until you can identify all individual blotches of blacks and whites.

Some monitors don't have enough range to show the difference between the darkest tones, or between the lightest tones. Sometimes you have to compromise.

You could try these pages as a reference:

... or my own striped image at the bottom.

Note that the www.lagom.nl stuff on monitors is quite interesting.


2.2 Contrast first

Tweaking brightness and contrast is often all that it takes. You may want to disable all sorts of additional effects and options. Read the documentation (if there is any) or find the meaning of menus on the Internet.

(Some prefer to adjust brightness first. Like me. Maybe it depends on the monitor?)

Still, contrast...

... is the most dangerous setting of all. Typically, contrast settings are too high, but people tend to like overly saturated stuff, so turning your screen contrast settings too low may result in accidentally 'over exposing' your work on the computer, making it 'over saturated' on the mobile device.

Another problem is that with contrast too low, regular use of the computer may cause eyestrain, as it becomes harder to recognize objects / controls on screen. (The opposite is also possible, you might actually get a headache from factory contrast settings!)Adjust if needed, but control yourself.

Myself I try to first calibrate without touching contrast at all, then I reset everything to factory settings and calibrate a second time, this time with eventual adjustments to contrast. Hey, nobody said it would be easy!


2.3 Brightness

You mostly fiddle with brightness to bring two monitors in alignment.


3.1 Color adjustment first monitor (versus reference)

After that adjust the colors on your monitor to match your reference, but don't overdo it! Limit yourself!

Note that there are huge differences in brightness between portable devices and monitors. You probably want to leave brightness and contrast alone at this stage... but... you may need to adjust contrast to be able to see all different colors / shades. Handle with care.


3.2 Grey bleed

Some screens become all grey if there's nothing to show. If that's the case make sure there is more on screen than just a small section of black - grey - white blocks.


4.1 Second monitor B&W

If you have a second monitor, then start with adjusting for black and white on that second monitor. Then adjust it until it matches the brightness of your first monitor.


4.2 Colors on screen one and two

Next adjust the colors on the second screen to match the first one (which may require very, very minor tweaks on the first one as well, but this may cause a deviation from any reference).

Repeat ad nauseum. And be done with it.


Note on order

Note: you might want to execute the steps in a different order, depending on your preferences and kit. The above is just my prefered order.


Note on calibrating for print / paper

Properly calibrating a monitor for print (or professional video editing) is incredibly hard.

You could try to match the screen to a color chart, but it's probably better to go for a colorimeter and simply forget about any cheap solution... And then there's your printer as well...


Example

My primary screen is an Ilyama ProLite XB3270QS, 2560x1440, 16:9, the cheapest 32" around, perhaps 2 years old.

My secondary screen is a HP ZDisplay 24, 1920x1200, 16:10, a ten (?) year old 2nd hand 24" screen, which I grabbed when my employer threw it away. (I think I'll grab myself another one.)

The much older HP is much brighter than the Ilyama, has a blue cast, but way better blacks and way less 'grey bleed' (where the whole screen turns grey if there's nothing to show). In general, it's much better than the newer Ilyama.

I created a horizontal color image (look at the bottom) and eyeballing it I ended up with the following settings, tweaking the hardware settings in the monitor (not tweaking the windows or graphic card settings):


Ilyama

  • Brightness 85 (was 80)
  • User Color
    • Red 98
    • Green 98
    • Blue 100

HP

  • Brightness 70 (was 100!)
  • Custom Color
    • Blue 250 (was 255)


When examining the settings it's clear the Ilyama is less bright than the much older HP, but it's larger and uses less energy.

Both screens now match my Galaxy A54 and one another fairly well. I'll guess I'll settle for this. I could up the brightness a bit, but I found higher settings tiring.

I didn't modify contrast at all, to me the contrast was fine.

If someone in the region of Rotterdam, The Netherlands, wants to lent me a color meter I can check how bad my eyes and color sense are 😏


Results

Real world result (apologies for reflections and fingerprints 😏, click to enlarge). The tablets were not calibrated. The old Lenovo tablet gave a surprisingly decent image, the more recent S6 Lite I left in vivid mode. The phone I used as a reference (the Galaxy A54) isn't in the image, as I used it to take the picture 😁


Why such an odd pair of monitors?

Historical reasons, mostly 😇

The Ilyama was my new screen during Covid. I actually have two (don't ask), but two 32" screens starts hurting your neck. The best option is still two 27" screens.

So I settled for one 32", and wanted a secondary screen with some reasonable screen estate. I typically use it to 'park' secondary apps, like a VM, Discord, things like that. I used a 22" for a while, both in landscape and portrait, but found it too small. I tried a full 27", and found it too large. There's also the dpi difference, making windows look odd when dragging them from one screen to the next.

The old ZDisplay24 is 24" (with some big bevels) but it's about the right size to place it above my TouchPortal tablets. It also has almost the same dpi as the Ilyama screen, so windows on both screens look similar, as do fonts and controls. So yeah, my setup is a little odd, but it works for me.


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